Fomu Hacker supports dual spi, so add a "spiflash4x" definition. The litex spi_flash module will run this flash in dual mode, because the `dq` array is only two signals wide. Signed-off-by: Sean Cross <sean@xobs.io>
- use 1e9/freq for default_clk_period - add default serial on tinyfpga_bx - use S6PLL on minispartan6 - add SPIFlash pins on versa_ecp5